|
FAQ's ABOUT EYEWEAR and EYE-CARE
Q. What is the difference between bifocals,
multifocals, and trifocals?
A. Bifocals are lenses that have two parts - the upper
part is used for distance vision, and the lower part is used
for such close vision tasks as reading or sewing. Even though
bifocals can technically be considered multifocals (because
they have more than one focus), the term "multifocal"
is generally used interchangeably with the term "trifocal",
because they have three or more segments. In trifocals, the
upper part helps view distant objects, the intermediate segment
is effective for arms-length vision, and the lower section
is for reading-distance vision.
Q. Are anti-reflective coatings really
worth the added expense?
A. Many people who use lenses with an anti-reflective
coating would wholeheartedly agree that they are worth every
cent. Recent research showed that approximately 14% of all
lenses sold in the U.S. have anti-reflective coatings. In
Europe, however, more than 60% of all lenses are "A-R"
coated. Anti-reflective lenses make use of metallic oxides
that "coat" lens surfaces and help to reduce annoying
reflections. A-R coatings also help to improve vision by reducing
"ghost" images and light reflections that are both
irritating and distracting. The "clear" appearance
that A-R coatings give makes the process particularly popular
among TV personalities.
Keep in mind however, that if you ask a former A-R user, they
may warn you against the coating, which was once prone to
crack and delaminate. But rest assured, newly developed techniques
have dramatically improved the quality, reliability, and performance
of A-R coatings.
Q. What does it mean if I have astigmatism?
A. In astigmatism, the eye's surface is shaped somewhat
like a football (more oval), rather than like a baseball (round).
Astigmatism causes the eye to focus on objects in two planes,
only one of which is able to focus on the retina. In this
case, out-of-round cylindrical lenses, opposite in design
to those of the astigmatic eye, are prescribed to "neutralize"
the defect.
Q. How safe is laser corrective surgery?
A. The procedure has proved quite safe thus far. There
have been no reported cases of blindness in relation to either
of the two most common procedures, PRK and LASIK. However,
the FDA is aware of a few cases of severe eye injury requiring
cornea transplant.
Q. How effective is laser eye surgery?
A. Most physicians agree that the treatment is generally
effective. According to an article printed in the July-August
'98 issue of the FDA Consumer Magazine, the treatment does
seem to be permanent, although as people age and their eyes
change, re-treatment may be necessary. It is also difficult
to predict how your eyes will respond to the surgery, which
means that you may still need corrective lenses for good vision,
even after undergoing the procedure. In some cases, patients
will need to undergo a second procedure. Unfortunately, some
patients even find that after refractive surgery, their best
obtainable vision with corrective lenses is worse than it
was before being operated on. This can occur as a result of
irregular tissue removal or the development of cornea haze.
In others, the effect of the surgery can be gradually lost
over several months. Again, re-treatment is an option.
"Halo Effect" is also a risk. The halo effect is
noticed in dim light. As the pupil enlarges, a second faded
image is produced. For some patients who have undergone the
PRK or LASIK procedures, this can interfere with night driving.
The FDA also reports that even when everything goes perfectly,
there are effects that might cause some dissatisfaction. Older
patients should be aware that they cannot have both good distance
vision and good near vision in the same eye without corrective
lenses.
Finally, if one eye is being treated at a time, the eyes may
not work well together between treatments. If a contact lens
wonðt be tolerated on the eye not yet operated on, work and
driving can be difficult or even impossible.
Q. What is the difference between an ophthalmologist, an optometrist,
and an optician?
A. For this answer, we looked to Jeffrey Anshel, author
of Smart Medicine for Your Eyes (Avery Publishing Group, 1999):
There are three different kinds of professionals involved
with the care of the eyes, so it may not come as a surprise
to you that there is some confusion over who does what. An
ophthalmologist is a medical doctor (MD) who specializes in
eye health and disease. After graduating from medical school,
an ophthalmologist spends three more years learning about
the diseases and surgeries of the eye (all ophthalmologists
are surgeons). In order to become a board certified ophthalmologist,
the MD must pass a written and practical certifying examination
in the specialty of ophthalmology. In telephone directories,
ophthalmologists are listed under the general heading of "physicians".
An optometrist is a doctor of optometry (OD). Optometrists
are defined as healthcare professionals trained and state
licensed to provide primary eyecare services. These services
include; comprehensive eye health and vision examinations,
diagnosis and treatment of eye diseases and vision disorders,
detection of general health problems, the prescription of
glasses and contact lenses, low vision rehabilitation, vision
therapy and medication, the performance of certain surgical
procedures, and the counseling of patients regarding their
surgical alternatives and vision needs. Optometrists complete
pre-professional undergraduate education at a college or university
and four years of professional education at a college of optometry.
Some optometrists also complete residencies. An optician is
a technician trained to fill prescriptions for lenses written
by optometrists and ophthalmologists. Opticians are trained
to make glasses, fit eyeglass lenses into frames, and adjust
frames to people's faces. In some states, they are also allowed
to do fittings of contact lenses. Opticians generally have
an associate college degree, which is awarded for completing
a two-year undergraduate program.
Q. How does diabetes affect the eye?
A. Diabetes, a disease that prevents your body from
making or using insulin to break down sugar in your bloodstream,
can cause changes in nearsightedness, farsightedness, and
premature presbyopia. In fact, the early signs of diabetes
are often detected during eye examinations. Diabetes can lead
to cataracts, glaucoma, and decreased eye-muscle coordination
and cornea sensitivity. Symptoms include fluctuating or blurred
vision, occasional double vision, loss of visual field, or
flashes and floaters within the eyes. However, the most serious
diabetes-related eye problem is diabetic retinopathy.
Q. What is retinopathy?
A. Diabetic retinopathy is a weakening or a swelling
of the tiny blood vessels in the retina of the eye, which
can result in blood leakage, the growth of new blood vessels,
as well as other changes. If left untreated, diabetic retinopathy
can lead to blindness. Once damage has occurred, it is usually
permanent, so it is important to control your diabetes as
much as possible to reduce the risk of developing retinopathy.
Frequent visits to your eyecare physician are also essential,
since early detection is crucial.
Q. Do certain things put me at risk
for developing retinopathy?
A. Several factors can increase the risk of developing
retinopathy, including; smoking, high blood pressure, alcohol
use, and pregnancy. (Source: http//www.virtualcity.com/dvc/diabetes.html)
Q. What is presbyopia? And what causes
it?
A. Presbyopia is a vision condition in which your eyes
have difficulty focusing on close objects due to a loss of
flexibility in the crystalline lens of the eye. Although our
eyes stop growing at age 10, the lens continues to produce
cells. Due to this growth, as well as the aging process, the
lens can lose some of its elasticity and, therefore, its ability
to focus.
Q. At what age does presbyopia become
a problem?
A. It's different for everyone. Actually, presbyopia
doesn't have a sudden onset; it develops over a number of
years. The condition will usually become noticeable in your
mid-40s.
Q. What are the symptoms of presbyopia?
A. If your arms are too short to see reading materials
anymore, that's a pretty good sign. At normal reading distance,
you will notice blurred vision, while close work will fatigue
your eyes and bring on a headache. An optometric examination
that tests your near-vision ability can determine presbyopia.
Once diagnosed, you will need glasses for reading or general
close vision - although you may find that wearing your glasses
all the time is best. Because the effects of presbyopia will
continue to change through your 60s, periodic lens changes
will most likely be necessary.
|